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本文以 kali-linux-2023.2-vmware-amd64 为例。

1：dig

dig 是域名系统（DNS）查询工具，常用于域名解析和网络故障排除。比 nslookup 有更强大的功能。

基本语法：
dig [选项]

2：选项介绍

选项总览：

┌──(root㉿kali)-[~]
└─# dig -h              
Usage:  dig [@global-server] [domain] [q-type] [q-class] {q-opt}
            {global-d-opt} host [@local-server] {local-d-opt}
            [ host [@local-server] {local-d-opt} [...]]
Where:  domain    is in the Domain Name System
        q-class  is one of (in,hs,ch,...) [default: in]
        q-type   is one of (a,any,mx,ns,soa,hinfo,axfr,txt,...) [default:a]
                 (Use ixfr=version for type ixfr)
        q-opt    is one of:
                 -4                  (use IPv4 query transport only)
                 -6                  (use IPv6 query transport only)
                 -b address[#port]   (bind to source address/port)
                 -c class            (specify query class)
                 -f filename         (batch mode)
                 -k keyfile          (specify tsig key file)
                 -m                  (enable memory usage debugging)
                 -p port             (specify port number)
                 -q name             (specify query name)
                 -r                  (do not read ~/.digrc)
                 -t type             (specify query type)
                 -u                  (display times in usec instead of msec)
                 -x dot-notation     (shortcut for reverse lookups)
                 -y [hmac:]name:key  (specify named base64 tsig key)
        d-opt    is of the form +keyword[=value], where keyword is:
                 +[no]aaflag         (Set AA flag in query (+[no]aaflag))
                 +[no]aaonly         (Set AA flag in query (+[no]aaflag))
                 +[no]additional     (Control display of additional section)
                 +[no]adflag         (Set AD flag in query (default on))
                 +[no]all            (Set or clear all display flags)
                 +[no]answer         (Control display of answer section)
                 +[no]authority      (Control display of authority section)
                 +[no]badcookie      (Retry BADCOOKIE responses)
                 +[no]besteffort     (Try to parse even illegal messages)
                 +bufsize[=###]      (Set EDNS0 Max UDP packet size)
                 +[no]cdflag         (Set checking disabled flag in query)
                 +[no]class          (Control display of class in records)
                 +[no]cmd            (Control display of command line -
                                      global option)
                 +[no]comments       (Control display of packet header
                                      and section name comments)
                 +[no]cookie         (Add a COOKIE option to the request)
                 +[no]crypto         (Control display of cryptographic
                                      fields in records)
                 +[no]defname        (Use search list (+[no]search))
                 +[no]dns64prefix    (Get the DNS64 prefixes from ipv4only.arpa)
                 +[no]dnssec         (Request DNSSEC records)
                 +domain=###         (Set default domainname)
                 +[no]edns[=###]     (Set EDNS version) [0]
                 +ednsflags=###      (Set EDNS flag bits)
                 +[no]ednsnegotiation (Set EDNS version negotiation)
                 +ednsopt=###[:value] (Send specified EDNS option)
                 +noednsopt          (Clear list of +ednsopt options)
                 +[no]expandaaaa     (Expand AAAA records)
                 +[no]expire         (Request time to expire)
                 +[no]fail           (Don't try next server on SERVFAIL)
                 +[no]header-only    (Send query without a question section)
                 +[no]https[=###]    (DNS-over-HTTPS mode) [/]
                 +[no]https-get      (Use GET instead of default POST method while using HTTPS)
                 +[no]http-plain[=###]    (DNS over plain HTTP mode) [/]
                 +[no]http-plain-get      (Use GET instead of default POST method while using plain HTTP)
                 +[no]identify       (ID responders in short answers)
                 +[no]idn            (convert international domain names)
                 +[no]ignore         (Don't revert to TCP for TC responses.)
                 +[no]keepalive      (Request EDNS TCP keepalive)
                 +[no]keepopen       (Keep the TCP socket open between queries)
                 +[no]multiline      (Print records in an expanded format)
                 +ndots=###          (Set search NDOTS value)
                 +[no]nsid           (Request Name Server ID)
                 +[no]nssearch       (Search all authoritative nameservers)
                 +[no]onesoa         (AXFR prints only one soa record)
                 +[no]opcode=###     (Set the opcode of the request)
                 +padding=###        (Set padding block size [0])
                 +qid=###            (Specify the query ID to use when sending queries)
                 +[no]qr             (Print question before sending)
                 +[no]question       (Control display of question section)
                 +[no]raflag         (Set RA flag in query (+[no]raflag))
                 +[no]rdflag         (Recursive mode (+[no]recurse))
                 +[no]recurse        (Recursive mode (+[no]rdflag))
                 +retry=###          (Set number of UDP retries) [2]
                 +[no]rrcomments     (Control display of per-record comments)
                 +[no]search         (Set whether to use searchlist)
                 +[no]short          (Display nothing except short
                                      form of answers - global option)
                 +[no]showbadcookie  (Show BADCOOKIE message)
                 +[no]showsearch     (Search with intermediate results)
                 +[no]split=##       (Split hex/base64 fields into chunks)
                 +[no]stats          (Control display of statistics)
                 +subnet=addr        (Set edns-client-subnet option)
                 +[no]tcflag         (Set TC flag in query (+[no]tcflag))
                 +[no]tcp            (TCP mode (+[no]vc))
                 +timeout=###        (Set query timeout) [5]
                 +[no]tls            (DNS-over-TLS mode)
                 +[no]tls-ca[=file]  (Enable remote server's TLS certificate validation)
                 +[no]tls-hostname=hostname (Explicitly set the expected TLS hostname)
                 +[no]tls-certfile=file (Load client TLS certificate chain from file)
                 +[no]tls-keyfile=file (Load client TLS private key from file)
                 +[no]trace          (Trace delegation down from root [+dnssec])
                 +tries=###          (Set number of UDP attempts) [3]
                 +[no]ttlid          (Control display of ttls in records)
                 +[no]ttlunits       (Display TTLs in human-readable units)
                 +[no]unknownformat  (Print RDATA in RFC 3597 "unknown" format)
                 +[no]vc             (TCP mode (+[no]tcp))
                 +[no]yaml           (Present the results as YAML)
                 +[no]zflag          (Set Z flag in query)
        global d-opts and servers (before host name) affect all queries.
        local d-opts and servers (after host name) affect only that lookup.
        -h                           (print help and exit)
        -v                           (print version and exit)

3：示例

示例 3-1：查询 www.baidu.com 的 DNS 信息。

dig www.baidu.com

结果：

解释：

; <<>> DiG 9.18.13-1-Debian <<>> www.baidu.com    # dig 版本和要查询的域
;; global options: +cmd    # 全局选项，dig 可以查询多个域，这里显示应用于所有查询的选项。默认为 +cmd

;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 8425
# 输出从 DNS 返回的技术信息
# opcode（操作码）：QUERY（查询），IQUERY（反查询），STATUS（监测状态）等。
# status（状态）：NOERROR 表示请求查询成功。
# id：一个随机的将请求与响应绑定在一起的数字。

;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
# qr（query）
# rd（recursion desired）
# ra（recursion avaliable）
# aa（authoritative answer）代表权威域名服务器作出了响应
# QUERY：查询数量 
# ANSWER：结果数量
# AURHORITY：来自权威域名服务器的结果数量
# ADDITIONAL：附加信息，当其值大于1的时候才会看到额外信息

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; MBZ: 0x0005, udp: 4096
# 选择伪切片

;; QUESTION SECTION:
;www.baidu.com.                 IN      A
# 查询字段，显示要查询的域名以及查询的服务
# IN（Internet）表示互联网查询
# A（Address）表示 A 记录查询，即主机查询

;; ANSWER SECTION:
www.baidu.com.          5       IN      CNAME   www.a.shifen.com.
www.a.shifen.com.       5       IN      A       110.242.68.3
www.a.shifen.com.       5       IN      A       110.242.68.4
# 查询结果

;; Query time: 8 msec
;; SERVER: 192.168.8.2#53(192.168.8.2) (UDP)
;; WHEN: Tue Jul 11 02:15:44 EDT 2023
;; MSG SIZE  rcvd: 101
# 请求所花的时间，DNS 服务器，当前时间，查询信息的大小

示例 3-2：只显示简要信息，而不显示任何其他信息。

dig www.baidu.com +short

结果：

示例 3-3：查询域名的邮件交换（MX）记录。

dig google.com MX

结果：

示例 3-4：查看 txt 记录。

dig google.com TXT

示例 3-5：得到最基本的 DNS 查询结果，不包含注释、问题、权威、附加和统计信息。

dig baidu.com +nocomments +noquestion +noauthority +noadditional +nostats

示例 3-6：反向查询与指定 IP 地址相关联的域名。

dig -x 114.114.114.114

示例 3-7：指定 DNS 服务器对相同的域名解析。

dig @114.114.114.114 www.baidu.com

示例 3-8：显示 DNS 查询的整个路由。

dig +trace baidu.com

示例 3-9：指定 DNS 服务端口号。如果 DNS 服务标准端口 53 被更改则可以使用此命令。

dig -p 5300 www.baidu.com

4：其他

其他资料：

《dig 命令的学习》：
https://blog.csdn.net/u014029795/article/details/87226813

《linux 命令总结之 dig 命令》：
https://blog.csdn.net/GzmObject/article/details/124696962

《How to Use the Dig Command in Linux》：
https://www.hostinger.com/tutorials/how-to-use-the-dig-command-in-linux/

《DIG command: Query name servers》：
https://www.ibm.com/docs/en/zos/2.1.0?topic=command-dig-query-name-servers

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知我者，谓我心忧；不知我者，谓我何求。

——《黍离》（先秦）